Generation of Effective Negative Impedance using RF Reconfigurable Signal Source

Načinjen je kratak pregled općenito metamaterijala, a posebice aktivnih metamaterijala ostvarenih upotrebom ne-Fosterovih elemenata. Napravljena je detaljnija matematička analiza nekoliko spojeva s negativnim elementima, te dana shema spoja koji ima mogućnost primjene kod prilagođenja antena. Sklop ostvaren negativnim kapacitetom i izvorom signala preko operacijskog pojačala projektiran je i simuliran u simulatoru mreža ADS. Zaključeno je da se sklop uvelike približava stvarnoj primjeni kod prilagođenja uz napomenu da najprije treba detaljnije proučiti stabilnost spoja kako bi bila u potpunosti objašnjena. Na laboratorijskom prototipu negativnog kapaciteta obavljena su mjerenja, te su prikazani rezultati mjerenja i njihova analiza.A short and general overview about metamaterials was made, especially about active metamaterials generated by non-Foster elements. A detailed mathematical analysis using negative elements was made as well, and a circuit schematic is given that can be used in antenna matching. New model achieved by using negative capacitor and signal source realized with amplifier was designed and simulated in Advanced Design System. It was concluded that the circuit was getting much closer to the actual applications in matching circuits, but the stability should be tested in more details to be fully explained. Measurements were performed on a laboratory prototype of a negative capacitor, and the results and their analysis were presented